U.S. patent application number 15/827355 was filed with the patent office on 2019-05-30 for system and method for detecting failure of a pressure sensor in a fire pump system.
The applicant listed for this patent is TORNATECH INC.. Invention is credited to MARC GOUPIL, FRAN OIS HARVEY.
Application Number | 20190162180 15/827355 |
Document ID | / |
Family ID | 66634988 |
Filed Date | 2019-05-30 |
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United States Patent
Application |
20190162180 |
Kind Code |
A1 |
GOUPIL; MARC ; et
al. |
May 30, 2019 |
SYSTEM AND METHOD FOR DETECTING FAILURE OF A PRESSURE SENSOR IN A
FIRE PUMP SYSTEM
Abstract
An automatic failure detecting device for detecting failure in a
pressure sensor for a fire pump controller, the failure detecting
device comprising a three-way valve connecting the pressure sensor
to a water line, wherein when the three-way valve is activated, the
pressure sensor is exposed to the atmosphere to measure the
atmospheric pressure, and wherein the failure detection device
signals a fault if said measured atmospheric pressure differs from
a standard expected value.
Inventors: |
GOUPIL; MARC; (ST-EUSTACHE,
CA) ; HARVEY; FRAN OIS; (MONTREAL, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TORNATECH INC. |
Montreal |
|
CA |
|
|
Family ID: |
66634988 |
Appl. No.: |
15/827355 |
Filed: |
November 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 51/00 20130101;
A62C 35/68 20130101; A62C 37/50 20130101; F04B 49/022 20130101;
F04B 49/10 20130101 |
International
Class: |
F04B 51/00 20060101
F04B051/00; A62C 37/50 20060101 A62C037/50 |
Claims
1. An automatic failure detecting device for detecting failure in a
pressure sensor for a fire pump controller, the failure detecting
device comprising a three-way valve connecting the pressure sensor
to a water line, wherein when said three-way valve is activated,
the pressure sensor is exposed to the atmosphere to measure the
atmospheric pressure, and wherein the failure detection device
signals a fault if said measured atmospheric pressure differs from
a standard expected value.
2. A method for automatically detecting failure in a pressure
sensor for a fire pump controller, the method comprising the steps
of: exposing the pressure sensor to the atmosphere by activating a
three-way valve connecting the pressure sensor to a water line;
measuring an atmospheric pressure; comparing said measured
atmospheric pressure to a standard expected value; and signaling a
fault if said measured atmospheric pressure and said standard
reading differ.
3. The method of claim 2, wherein the pressure sensor is exposed to
the atmosphere once per day.
Description
TECHNICAL FIELD
[0001] The present disclosure concerns automatic failure detection
in a pressure sensor of a fire pump controller.
BACKGROUND OF THE INVENTION
[0002] Fire pumps are needed when local municipal water systems,
for example public underground water supplies, tanks, reservoirs
and lakes, cannot provide sufficient pressure to meet the hydraulic
design requirements of a fire sprinkler system. This usually occurs
if a building is very tail, or if the system requires a relatively
high terminal pressure at the fire sprinklers in order to provide
large volumes of water, such as in storage warehouses. Fire pumps
are also needed when the water supply is provided by a ground level
water storage tank.
[0003] Fire pump controllers are usually equipped with a pressure
sensor that is responsible for activating the pump in case of fire.
The pressure sensor senses the water pressure in the sprinkler
system's water line. In the event of a fire, the sprinkler system
activates to spray water, thus lowering the water pressure in the
water line. The fire pump controller is configured to activate the
fire pump in the event that the pressure in the water line drops
below an activation threshold, and to stop the pump when the water
pressure rises above a stopping threshold. A proper working sensor
is vital to the functioning of the fire system, and is thus a
critical component.
[0004] Unfortunately, sensors have often been the subject of
material or manufacturing problems. A noted defect is an offset in
the response of the sensor under pressure, either downwards or
upwards, while still maintaining the correct linearity of the
response profile. Such a situation is dire, as a change in the
response of a sensor can cause untimely activations of the pump, or
worse, prevent its activation in the event of an actual pressure
drop.
[0005] To resolve the above-mentioned problem, certain fire pump
controllers have been equipped with a second redundant pressure
sensor to corroborate the information provided by the main sensor.
If the two readings are not the same, the system is notified. This
technique suffers from certain drawbacks: there is a cost
associated with adding a second sensor, and more importantly, it is
extremely difficult to determine which of the two sensors is the
faulty one.
SUMMARY OF THE INVENTION
[0006] It is an object of the present disclosure to provide
automatic failure detection in a pressure sensor for a fire pump
controller that requires no additional redundant pressure sensor
and allows for the detection of a faulty sensor with greater
precision.
[0007] Accordingly, the present disclosure provides an automatic
failure detecting device for detecting failure in a pressure sensor
for a fire pump controller, the failure detecting device comprising
a three-way valve connecting the pressure sensor to a water line,
wherein when the three-way valve is activated, the pressure sensor
is exposed to the atmosphere to measure the atmospheric pressure,
and wherein the failure detection device signals a fault if said
measured atmospheric pressure differs from a standard expected
value.
[0008] There is also provided a method for automatically detecting
failure in a pressure sensor for a fire pump controller, the method
comprising the steps of exposing the pressure sensor to the
atmosphere by activating a three-way valve connecting the pressure
sensor to a water line, measuring an atmospheric pressure,
comparing the measured atmospheric pressure to a standard expected
value, and signaling a fault if the measured atmospheric pressure
and the standard reading differ.
[0009] In an embodiment, the pressure sensor is exposed to the
atmosphere once per day.
[0010] All of the foregoing and still further objects and
advantages of the invention will become apparent from a study of
the following specification, taken in connection with the
accompanying drawings wherein like characters of reference
designate corresponding parts throughout the several views.
BRIEF DESCRIPTION OF THE FIGURES
[0011] Embodiments of the disclosure will be described by way of
examples only with reference to the accompanying drawing, in
which:
[0012] FIG. 1 is a graphical depiction of various pressure sensor
response times;
[0013] FIG. 2A is a sketch of a failure detection device in an OFF
state, in accordance with an illustrative embodiment of the present
invention;
[0014] FIG. 2B is a sketch of a failure detection device in an ON
state, in accordance with an illustrative embodiment of the present
invention;
[0015] FIG. 3 is a graphical depiction of a pressure reading taken
by the failure detection device of FIG. 2B, in accordance with an
illustrative embodiment of the present invention; and
[0016] FIG. 4 is a schematic diagram of a fire pump controller
system, in accordance with an illustrative embodiment of the
present invention.
DETAILED DESCRIPTION
[0017] Referring to FIG. 1, there is shown a pressure-time graph
for various pressure sensor readings in a typical fire pump system.
For a properly functioning sensor, depicted by the curve "good
sensor", the pump motor is activated when the water pressure in the
water line drops below a "start" value (due to the sprinkler system
activating) and deactivates when the pressure in the water line
rises back above a "stop" value, signifying that the sprinkler
system is no longer being used and the pump has brought the water
pressure up to a suitable value. For a faulty sensor with an
upwardly offset pressure response, depicted by the curve "bad
sensor 1", a drop in pressure may never fall below the "start"
value, and thus the motor will not activate in the case of a fire.
In such a case, the water pressure will remain constant at a value
lower than that required for the sprinkler system to be effective.
Alternatively, for a faulty sensor with a downwardly offset
pressure response, the pressure reading may drop low enough to
initiate the pump, but never rise above the "stop value", causing
the pump to run continuously, eventually breaking. Therefore, it is
thus crucial to ensure that the pressure sensor being used is
providing accurate readings.
[0018] Referring now to FIG. 2A, there is shown a failure detection
device, generally referred to by the reference numeral 10, in its
OFF state. A three-way valve 12 positioned in the water line 14
replaces the standard valve (often a solenoid valve) typically
found in fire pump controllers for creating a leak in the line of
pressure to perform a start-up test. The three-way valve 12
comprises an inlet 16 for receiving water from the water line 14, a
main outlet 18 directed towards the sprinkler system (not shown), a
drain outlet 20 directed towards a drain (not shown), and a
pressure sensor 22 or pressure transducer "PT". In its OFF state,
the three-way valve 12 directs water from the inlet 16 to the main
outlet 18, and the pressure sensor 22 records the pressure of the
water entering the failure detection device 10 from the water
line.
[0019] Referring now to FIG. 2B, the failure detection device 10 is
shown in its ON state. In this state, the three-way valve 12 is
configured to direct water from the water line 14 entering the
failure detection device 10 from the inlet 16 to the drain outlet
20 rather than the main outlet 18. In this configuration, the
pressure sensor 22 is disconnected from the water line 14 and
exposed to the atmosphere. Thus, the pressure sensor 20 may record
pressure readings at atmospheric pressure.
[0020] Referring now to FIG. 3 in addition to FIGS. 2A and 2B, a
pressure-time graph displays pressure readings for various states
of the failure detection device 10. During the OFF states, the
pressure sensor 22 reads the pressure of the water passing through
the failure detection device 10 from the main line 14, which
remains consistent as long as the sprinkler system (not shown) is
not activated. During the ON state, the pressure sensor 22 is
exposed to the atmosphere, and thus records the atmospheric
pressure. In an embodiment, the pressure sensor 22 is calibrated to
read 0 PSI at atmospheric pressure. As such, in order to
periodically test the accuracy of the pressure sensor 22, the
failure detection device 10 is switched to its ON state by
activating the three-way valve 12 and exposing the pressure sensor
22 to the atmosphere. If the pressure sensor 22 provides a reading
of 0 PSI, then it is functioning properly. If the pressure sensor
22 does not provide a reading of 0 PSI, then failure has been
detected and the faulty pressure sensor 22 may be replaced. In an
embodiment, this test is performed daily or weekly to ensure
constant surveillance of the pressure sensor.
[0021] Referring now to FIG. 4, the failure detection device 10 is
connected to a fire pump controller logic 24. Receiving power from
a power source 26, the fire pump controller logic receives input
from the failure detection device 10 regarding the water pressure
in the water line 14. The fire pump controller 24 activates a fire
pump 28 when a drop in pressure in the water line 14 is detected
due to activation of a sprinkler system 30. When the failure
detection device 10 detects failure in the pressure sensor (not
shown), it alerts the fire pump controller logic 22.
[0022] The scope of the claims should not be limited by the
preferred embodiments set forth in the examples, but should be
given the broadest interpretation consistent with the description
as a whole.
* * * * *